Cellulose

The original sample material was too large to be fed directly into our Variable Speed Rotor Mill PULVERISETTE 14. We fed 24 grams of the original sample into the grinding vessel. One of the mills SOPs was set to grind in intervals of two seconds with maximum speed and one second of pausing time. The mill stopped after five cycles (10 seconds of total grinding time). The cellulose was ground to fine, fluffed up fibers. The majority of sample was comminute < 2 mm fine. Some fragments up to ~ 5 mm dia. were found.

Cleaning was performed rapidly by washing off with warm water. The equipment was dried after we flushed off the fine sample dust.

After the precutting of cellulose sample in result one, now about 6,5 grams of sample was fed and ground with the desired Variable Speed Rotor Mill PULVERISETTE 14 classic line. It would also be possible to manually cut the fragments < 1 cm and use a coarse 2 mm sieve ring for a precutting with our Variable Speed Rotor Mill PULVERISETTE 14, too.

The mill was equipped with a 12 ribs rotor and a sieve ring of 0,5 mm trapezoidal perforation. The prepared sample batch was fed continuously within 70 seconds. The grinding sound was smoother. A bit of fine sample dust was spinning with the moving air inside the feeding funnel of the machine.

After comminution, a lot of fluffed up cellulose was found inside the collecting vessel. The rotor was slightly covered with fine sample dust. On the edges of the rotor ribs, traces of cellulose were removed easily.

Below the rotor, sealing labyrinth disk was polluted moderately. A cleaning step would be required after this point (before fine sample dust will pass all three channels and enter the motor).

If higher amounts of sample should be ground, it is still possible to upgrade the mill with optional accessories for grinding large quantities or with one of our cyclone separators. Intensive cleaning was performed by washing off all grinding parts with soapy water. Afterwards, the equipment was flushed with fresh water and dried.

The grinding sound was similar to result two; the five grams were fed and ground within 40 seconds for this trial.

We opened the grinding chamber and found, that more sample stuck to the eight rotor ribs. Also here, the sample was ground and fluffed up. This particular sample was much brighter that the sample of result two, but also the start coloration was different.

There was no significant clogging of the used 0,5 mm sieve ring as well. Also here, fine sample dust entered the space below the rotor and polluted two of the three labyrinth disks.